Substrates comprising polyvinyl chloride have come into wide use as decorative coverings and particularly as decorative floor coverings. In order for such materials to be aesthetically acceptable, they must be provided with a colored pattern or design. Two general types of colorants have traditionally been available to provide such patterns; namely, dyes and pigments. The Encyclopedia of PVC defines dyes to be colorants that are soluble in vinyl formulations, whereas pigments are colorants that are insoluble in vinyl formulations. Dyes have primarily comprised disperse and solvent dyes; however, such dyes have been shown to have definite drawbacks which preclude their use in polyvinyl chloride systems. Thus, although they may be conveniently used in polyvinyl chloride-containing formulations to give products that have good transparency and color strength, problems associated with color bleeding, poor light fastness, lack of heat stability and the like have mitigated against their use and have resulted in the general adoption of pigments to provide color to polyvinyl chloride compositions.
Pigments are conventionally applied by means of printing inks, or by stencil deposition of pigmented particles. Nevertheless, pigmented products are not entirely satisfactory because, for example, the color selected is limited and through-color images cannot be obtained. Accordingly, industrial producers of products containing polyvinyl chloride have long sought ways to improve the color characteristics of such products.